Hemispherical optical projection systems and methods, i.e. systems and methods which project images at an angle of at least about 160 degrees, are used to project images onto the inner surfaces of domes. Hemispherical optical projection systems and methods have long been used in planetariums, commercial and military flight simulators and hemispherical theaters such as OMNIMAX.RTM. theaters. With the present interest in virtual reality, hemispherical optical projection systems and methods have been investigated for projecting images which simulate a real environment. Such images are typically computer-generated multimedia images including video, but they may also be generated using film or other media. Home theater has also generated much interest, and hemispherical optical projection systems and methods are also being investigated for home theater applications.
Heretofore, hemispherical optical projection systems and methods have generally been designed for projecting in a large dome having a predetermined radius. The orientation of the hemispherical projection has also generally been fixed. For example, planetarium projections typically project vertically upward, while flight simulators and hemispherical theaters typically project at an oblique angle from vertical, based upon the audience seating configuration. Hemispherical optical projection systems and methods have also generally required elaborate color correction and spatial correction of the image to be projected, so as to be able to project a high quality image over a hemisphere.
Virtual reality, home theater and other low cost applications generally require flexible hemispherical optical projection systems and methods which can project images onto different size domes and for different audience configurations. The optical projection systems and methods should also project with low optical distortion over a wide field of view, preferably at least about 160 degrees. Minimal color correction and spatial correction of the image to be projected should be required. A high intensity image should be projected, and it is desirable to have the capability of projecting three-dimensional images.